Nyctibates corrugatus Boulenger, 1904

Griesbaum, Frederic, Hirschfeld, Mareike, F. Barej, Michael, Schmitz, Andreas, Rohrmoser, Mariam, Dahmen, Matthias, Muehlberger, Fabian, Christoph Liedtke, H., L. Gonwouo, Nono, Doumbia, Joseph & Roedel, Mark-Oliver, 2019, Tadpoles of three western African frog genera: Astylosternus Werner, 1898, Nyctibates Boulenger, 1904, and Scotobleps Boulenger, 1900 (Amphibia, Anura, Arthroleptidae), Zoosystematics and Evolution 95 (1), pp. 133-160 : 147-149

Nyctibates corrugatus Boulenger, 1904

Material examined.

ZMB 82109, Gosner stage 25, Cameroon, Mt Kala, near Kala village, 848 m, 3°50'31.86"N, 11°21'4.32"E, 9 November 2015, leg. M.F. Barej, H.C. Liedtke & L.N Gonwouo; ZMB 82112, Gosner stage 25, Cameroon, Ebo Forest, Njuma, 311 m, 4°21'55.68"N, 10°25'18.48"E, 6 October 2011, leg. M. Dahmen; ZMB 82115, Gosner stage 26, Cameroon, Ebo Forest, Njuma, 255 m, 4°20'51.06"N, 10°13'35.04"E, 27 September 2010, leg. M. Hirschfeld & M.-O. Rödel; ZMB 82116, Gosner stage 25, Cameroon, Ebo Forest, Bekop, 825 m, 4°21'55.68"N, 10°25'18.48"E, 10 January 2011, leg. M. Hirschfeld & F. Grözinger; ZMB 88351 (GenBank MK318904), Gosner stage 25, Cameroon, Korup National Park, Esukutan, 422 m, 5°22'24.81"N, 8°59'51.35"E, 20 May 2014, leg. F. Mühlberger).

All tadpoles were collected from small to medium-sized forest streams. The description is mainly based on ZMB 82112 and ZMB 82115. The latter specimen was the bases of the description by Channing et al. (2012). The N. corrugatus tadpole was first described by Amiet (1971). The genotyped tadpole has been compared with an adult from the vicinity of Ediensoa, Cameroon (GenBank DQ283361). The two sequences were identical.

Description.

Very long and robust, but still slender tadpole with strong, muscular tail (Fig. 16); body oblong oval to almost rectangular in dorsal view (Fig. 16b shows some artificial shrinking), flattened and elongated in lateral view, belly region fatter than head; snout rounded in dorsal view, more narrowly rounded in lateral view; body length 38.0 ± 1.3% of total length; body height 29.0 ± 3.5% of body length; body width 39.5 ± 0.7% of body length; eyes positioned dorsolaterally, eye diameter 6.4 ± 0.9% of body length; nostrils positioned dorsolaterally, closer to snout tip than to eyes; inter-nostril distance 83.4 ± 4.9% of interorbital distance; tail fins narrow, ventral fin originating from tail base, dorsal fin originates at about first third of the tail; ventral fin height 76.5 ± 3.3%, than dorsal fin height; highest part of tail in the last third; body height 81.8 ± 8.3% of maximum tail height; tail axis width 53.4 ± 2.9% of body width; tail axis height 62.3 ± 6.8% of maximum tail height; tail tip pointed; vent tube dextral; body with large lateral air sacs, extending from spiracle to end of body; short spiracle, sinistral; mouth ventral, near snout and narrower than interorbital distance; labial tooth formula 1/1; anterior labium consists of two semicircular lobes, the edges carrying a row of short round marginal papillae, the gap between the two lobes very small; posterior labium a wide, flat lobe, carrying one row of about 20-30 uniform, short round marginal papillae, a few further, widely spaced small, wart-like papillae are arranged in one transversal row across the labium; heavily serrated, black jaws; upper jaw broadly arched with a medial fang, lower jaw broadly V-shaped without a notch.

The largest specimen (Gosner stage 25) measured 81 mm total length.

Coloration in preservation.

Body and tail including fins plain brown in preservation; ventrum brighter and more grayish; ventral fin brighter and more transparent than dorsal fin (Fig. 16). In life the tadpoles are dark brown to almost black with a blue tinge along the lower parts of flanks, belly and tail axis (Fig. 17). ZMB 82109 shows large areas of little or absent pigmentation, what might be a preservation artifact.